Heat Seal-Induced Pinholing in Double-Coated Paperboards

摘要

When polyethylene-coated paperboard cartons are heat sealed, water, trapped within the paperboard, is vaporized. If too much heat is applied, this pressurized vapor will blow through the memi-molten polyethylene coatings to form pinholes can occur before a good heat seal is acheived. Pinholing is best controlled with low melt index polyethylene coatings. THe lower a coating's melt index, the greater its resistance to heat-induced pinholing.